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P.O. Box 2CharlburyOxonOX7 3PDUK
Tel: 44(0)1608 810334Fax: 44(0)1608 811486email: [email protected]
Presented at Bath University, March 1st. 2006
Automotive Fuel Economy and the IVT
F.G.Perry
Perbury Engineering Ltd.
Eur.Ing, C.Eng, M.I.Mech.E, M.R.Ae.S
Perbury Engineering Ltd.
OUTLINE
Single Regime IVT (Infinitely Variable Transmission)
Fundamental Power Requirements
Perbury Multi-Regime IVT
Engine Optimum Operating Line
Typical Fuel Consumption
Bath University/NREL Simulation
Predictions for Perbury IVT
Summary – How to increase MPG
Conclusions
Perbury Engineering Ltd.
Road Load HP
0
10
20
30
40
50
60
70
0 20 40 60 80 100
MPH
RO
AD
LO
AD
H
P
Typical 2000 lb, 70 bhp car
Perbury Engineering Ltd.
Engine Fuel Map and Vehicle Gearing
0
20
40
60
80
100
1 2 3 4 5
Engine RPM – 000s
Tor
que
– lb
ft
80
60
30
MP
H
25
19 M
ph/1
000
rpm
34
40
MaxPower
240
250 g/kW.h
270
300
400
800
600
1000
90
MaximumTorque
Perbury Engineering Ltd.
Single Regime IVT
Perbury Engineering Ltd.
Perbury Engineering Ltd.
Perbury Engineering Ltd.
Perbury Engineering Ltd.
Pinion Speed Ratio W.O. Variable Ratio
-0.50
0.00
0.50
1.00
1.50
2.00
2.50
0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80
Variable Ratio
Pin
ion
Sp
ee
d R
atio
Low Regime
High Regime
Reverse
Perbury Engineering Ltd.
Regime Efficienciesincludes all parasitic losses
82
84
86
88
90
92
94
96
0.4 0.6 0.8 1 1.2 1.4 1.6 1.8
Variable Ratio
Eff
icie
ncy
%
Low
High
Reverse
Perbury Engineering Ltd.
Engine Fuel Map and Vehicle Gearing
0
20
40
60
80
100
1 2 3 4 5
Engine RPM – 000s
Tor
que
– lb
ft
80
60
30
MP
H
25
19 M
ph/1
000
rpm
34
40
MaxPower
240
250 g/kW.h
270
300
400
800
600
1000
90
OptimumLine
MaximumTorque
30
40
50
60
70
80 90
With efficiencies
Perbury Engineering Ltd.
Transmission ratio for minimum fuel consumptionincluding efficiencies
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
0 20 40 60 80 100MPH
Re
du
ctio
n |
Ove
rdri
veOverdrive bypass
Perbury Engineering Ltd.
MPG vs MPH at Constant Speed
0
10
20
30
40
50
60
70
20 30 40 50 60 70 80 90 100
MPH
Mile
s/U
K G
allo
n
Manual (97%)
Perbury Engineering Ltd.
MPG vs MPH at Constant Speed
0
10
20
30
40
50
60
70
20 30 40 50 60 70 80 90 100
MPH
Mile
s/U
K G
allo
n
0
20
40
60
80
100
120
140
% I
ncr
ea
se
IVT (84-94.5%) Manual (97%) % Increase
Perbury Engineering Ltd.
2000 Honda Insight Hybrid
Perbury Engineering Ltd.
Perbury Engineering Ltd.
Introduction to ADVISOR
ADVISOR, NREL’s ADvanced VehIcle SimulatOR, is a set of model, data, and script text files for use with Matlab and Simulink. It is designed for quick analysis of the performance and fuel economy of conventional, electric, and hybrid vehicles. ADVISOR also provides a backbone for the detailed simulation and analysis of user defined drivetrain components, a starting point of verified vehicle data and algorithms from which to take full advantage of the modeling flexibility of Simulink and analytic power of Matlab. ADVISOR was preliminarily written and used in November 1994. Since then, it has been modified as necessary to help manage the US DOE Hybrid Vehicle Propulsion System subcontracts. Only in January 1998 was a concerted development effort undertaken to clean up and document ADVISOR.
Since then, researchers at Chrysler Corp. General Motors Corp. AlliedSignal Automotive Argonne National Laboratory Naval Research Laboratory University of California-Davis University of Maryland University of Illinois-Urbana/Champaign and other research institutions have used ADVISOR to predict the performance of their vehicles, do studies on the effect of control strategy on emissions and fuel use, among other things.
Perbury Engineering Ltd.
MPG vs Minimum Engine RPMM
inim
um E
ngin
e S
peed
- R
PM
800
900
1000
1100
1200
1300
1400
1500
60 70 80 90 100 110 120 130
SC03
FTP
US06
HWFET
Av.Av. Accel
Cycle Stops Miles MPH ft/sec2
HWFET 1 10.26 48.2 0.64US06 5 8.01 47.97 2.2SC03 6 3.58 21.44 1.65FTP 22 11.04 16.04 1.68
Modified Min. Engine RPM
UK MPG
Perbury Engineering Ltd.
Starting Optimum Line
0
10
20
30
40
50
0 500 1000 1500 2000
Engine RPM
To
rqu
e -
lb
ft
Feasible
Used in thesimulation
Perbury Engineering Ltd.
Car Weight 2000 lbEngine bhp 50 kW maxSFC Max 0.35 lb/bhp.hr
213 g/kW.hr
Acceleration Times
0
2
4
6
8
10
12
14
0 10 20 30 40 50 60 70
MPH
Se
con
ds
Perbury Engineering Ltd.
MPG vs MPH - Honda Insight
0
20
40
60
80
100
120
140
160
20 30 40 50 60 70 80 90 100
MPH
MP
G (
UK
)
0
20
40
60
80
100
120
140
160
Incr
ea
se %
Simulationconstant speeds
3rd.
4th.
5th.
With manual
With IVT
Gear
Perbury Engineering Ltd.
MPG (UK)
% % Perbury
FTP 65.6 64.1 63.3 60.8 59.6 57.3 75.8 20.3 27.2 91.0
HWFET 89.9 79.0 84.8 76.6 79.0 81.1 101.9 20.2 29.0 122.4
US06 n/a 52.3 54.8 48.5 46.1 51.7 60.4 10.2 31.0 72.5
SC03 n/a 62.7 55.5 56.1 54.2 52.9 68.8 24.0 26.9 82.6
MPG at a constant 60 MPH 90.3 108.5
65 MPH 83.1 99.8
Official Combined MPG 94.8
MPG (US) Predictions for Perbury IVT
Drive Cycle
Pubd
DataNREL Test
Honda Simulation Results
HybridFolsom
CVT Manual Auto Perbury
Increase
Perbury
Perbury Engineering Ltd.
How to increase miles per gallon
ONLY AN IVT CAN DO ALL THIS AND STILL BESMOOTHLY DRIVABLE
Reduce engine speeds by high vehicle gearing
For a given transmission, select the final drive ratioto suit the vehicle speeds during bypass
After attaining maximum overdrive,bypass the rolling assembly
Keep to a chosen engine optimum linebut allow for transient departures
Perbury Engineering Ltd.
Changing from fixed ratios to IV can indeed increase MPG
An additional benefit - cars and traffic can be quieter as well
Simulation increases are approximately 20% better than the Honda Insight Hybrid and 30% better than the 5-speed manual
Even greater increases than this seem to be possible
Conclusions